A MOF-derived bimetallic oxide nanozyme and a preparation method and application thereof

Abstract

The application relates to a MOF-derived bimetallic oxide nanozyme, a preparation method thereof and application, and belongs to the technical field of nanometer material synthesis. The application first prepares a bimetallic MOF material by using simple room-temperature stirring self-assembly, and then synthesizes the MOF-derived bimetallic oxide nanozyme by using a simple pyrolysis method. The synthesis method is simple, low in cost, mild and stable, and is convenient for large-scale preparation. The MOF-derived bimetallic oxide nanozyme synthesized by the application has multiple free radical scavenging capacities, is good in biological safety, good in dispersity, good in stability and the like, and solves the problem that a traditional single-atom nanozyme needs to be further modified with a surfactant after preparation and can be used for biological detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanomaterial synthesis, and particularly relates to a MOF-derived bimetallic oxide nanozyme, a preparation method and application thereof. BACKGROUND

[0002] Compared with natural enzymes, nanozyme materials have the advantages of good stability, adjustable structure and composition, tunable catalytic activity and easy storage. At present, the reported nanozyme materials mainly include: (1) metal-based nanozyme materials, such as gold nanoparticles (AuNPs), platinum nanoparticles (PtNPs), silver nanoparticles (AgNPs) and their alloys; (2) metal oxide-based nanozyme materials, such as vanadium pentoxide (V2O5), cerium dioxide (CeO2), manganese dioxide (MnO2), cobalt trioxide (Co3O4), and ferromagnetic nanoparticles (Fe3O4NPs); (3) carbon-based nanozyme materials, such as graphene oxide, graphene quantum dots, carbon dots, carbon nitride, carbon nanotubes, carbon nanosheets and fullerenes; (4) other types of nanozyme materials, such as Prussian blue analogues, metal-organic frameworks (MOFs) and their derivatives, and single-atom nanozyme materials.

[0003] However, there is no report on the preparation of nanozyme using MOF doped with Pd derivatives, therefore, the application proposes a preparation method of Pd(NO3)2-Co-based bimetallic MOF derivative material, and uses the oxidase-like activity to construct a Pd-Co-based nanozyme biomolecular colorimetric sensing platform, thereby expanding the application of nanozyme in biomolecular analysis. SUMMARY

[0004] In view of the problems in the prior art, the purpose of the application is to provide a technical solution of a MOF-derived bimetallic oxide nanozyme, a preparation method and application thereof.

[0005] The application is implemented by the following technical solutions:

[0006] The application provides a preparation method of a MOF-derived bimetallic oxide nanozyme in the first aspect, which comprises the following steps:

[0007] 1) Dissolve benzimidazole in N,N'-dimethylformamide to prepare solution A;

[0008] 2) Dissolve cobalt nitrate hexahydrate in N,N'-dimethylformamide to prepare solution B;

[0009] 3) Stir and mix solution A and solution B uniformly, then add ammonia water dropwise into the mixed solution, stir and mix to prepare solution C;

[0010] 4) stirring the above solution C at room temperature, washing with ethanol, collecting the purple solid by centrifugation, drying overnight to obtain a purple solid powder S;

[0011] 5) mixing palladium nitrate with the above purple solid powder S in deionized water, stirring magnetically to obtain a suspension D;

[0012] 6) collecting the precipitate by centrifugation of the above suspension D, washing the precipitate with deionized water several times until the washing liquid is neutral, and freeze-drying the collected dark purple solid SS;

[0013] 7) placing the above dark purple solid SS in a crucible, heating in a muffle furnace, and cooling to room temperature to obtain a MOF-derived bimetallic nanoscale enzyme, i.e. PdCoO x nanoscale enzyme.

[0014] Further, the concentration of benzimidazole in solution A in step 1) is 2-3%.

[0015] Further, the concentration of cobalt nitrate in solution B in step 2) is 5-6%.

[0016] Further, the stirring mixing time of solution A and solution B in step 3) is 15-30 min, and the amount of ammonia added is 2-3% of the total of solution A and solution B.

[0017] Further, the stirring time of solution C at room temperature in step 4) is 3-5 hours.

[0018] Further, the mass ratio of palladium nitrate to purple solid powder S in step 5) is 1:3-5.

[0019] Further, the heating temperature of the muffle furnace in step 7) is 300-400°C, and the heating time is 2-3 hours.

[0020] The second aspect of the present application provides a MOF-derived bimetallic oxide nanoscale enzyme obtained by any of the above preparation methods.

[0021] In some embodiments, the PdCoO x nanoscale enzyme prepared by the present application has a pore size of 10-20 nm and a specific surface area of 70-100 m 2 / g.

[0022] In some embodiments, the PdCoO x nanoscale enzyme prepared by the present application has an atomic molar ratio of Pd:Co:O of (7-9):(16-20):(60-70).

[0023] The third aspect of the present application provides an application of the MOF-derived bimetallic oxide nanoszyme obtained above as an oxidase, and the oxidase activity is similar to that of oxidase protein in organisms, and strong free radicals can be generated in the presence of oxygen, thereby oxidizing the substrate, and more specifically, the oxidase (OXD), peroxidase (POD), catalase (CAT), superoxide dismutase (SOD) activity, and the like.

[0024] The fourth aspect of the present application provides an application of the MOF-derived bimetallic oxide nanoszyme obtained above in free radical scavenging, and the MOF-derived bimetallic oxide nanoszyme directly scavenges ·OH as an electron donor.

[0025] The present application has the following beneficial effects:

[0026] The present application first uses simple room temperature stirring self-assembly to prepare a bimetallic MOF material, and then uses a simple pyrolysis method to synthesize a MOF-derived bimetallic oxide nanoszyme. The synthesis method is simple, low in cost, mild and stable in conditions, and is convenient for large-scale preparation.

[0027] The MOF-derived bimetallic oxide nanoszyme synthesized in the present application has multiple free radical scavenging capabilities, good biological safety, good dispersibility, and good stability, and solves the problem that a traditional single-atom nanoszyme needs to be further modified with a surfactant after preparation for use in biological detection. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 PdCoO x Transmission electron microscope characterization (A) and photoelectron spectroscopy analysis (B) of the nanoszyme. The photoelectron spectroscopy analysis shows that the materials Pd, Co, and O in Example 1 are uniformly distributed in the material.

[0029] Figure 2 Oxidase activity of the nanoszyme prepared in Example 1 and Comparative Examples 1 and 2.

[0030] Figure 3 Application of PdCoO x Detection of H2O2 (A) and glucose (B) by the nanoszyme.

[0031] Figure 4 Free radical scavenger vitamin C (O2 ·- and ·OH scavenger), NaN3 1 O2 scavenger), thiourea (TH) (·OH scavenger), and p-benzoquinone (PBQ) (O2 ·- scavenger) on system A652, indicating that the MOF-derived bimetallic nanoszyme directly scavenges ·OH as an electron donor. DETAILED DESCRIPTION

[0032] The present application is further illustrated in conjunction with the following examples.

[0033] Example 1:

[0034] Step 1: 2.3g of benzimidazole was dissolved in 100mL of N,N'-dimethylformamide (DMF) to form solution A;

[0035] Step 2: 2.2g of cobalt nitrate hexahydrate was dissolved in 40mL of DMF to form solution B;

[0036] Step 3: The above solution A and solution B were uniformly mixed under stirring for 20min, and then 3mL of ammonia was added dropwise to the mixture to form solution C;

[0037] Step 4: After the above solution C was stirred at room temperature for 3h, the purple solid was collected by centrifugation after washing with ethanol three times, and the purple solid powder S was obtained by drying at 70℃ overnight;

[0038] Step 5: Palladium nitrate was mixed with the above purple solid powder S in a mass ratio of 1:3 in 50mL of deionized water; magnetic stirring for 12h, to obtain suspension D;

[0039] Step 6: The precipitate was collected by centrifugation, and the precipitate was washed with deionized water several times until the washing liquid was neutral, and the collected dark purple solid SS was freeze-dried;

[0040] Step 7: The dark purple solid SS in step six was placed in a crucible and heated in a muffle furnace at 300℃ for 2h, and cooled to room temperature to obtain PdCoO x nanozyme;

[0041] As Figure 1 shown: Transmission electron microscope characterization (A) and photoelectron spectroscopy analysis (B) of PdCoO x nanozyme. Photoelectron spectroscopy analysis showed that Pd, Co, and O in the material prepared in Example 1 were uniformly distributed in the material.

[0042] Among them, the pore size of PdCoO x nanozyme prepared in Example 1 is 10-20nm, and the specific surface area is 80-120m 2 / g. The atomic molar ratio of Pd:Co:O in PdCoO x nanozyme is 8.88:17.49:65.88.

[0043] Comparative Example 1:

[0044] Step 1: 2.3g of benzimidazole was dissolved in 200mL of N,N'-dimethylformamide (DMF) to form solution A;

[0045] Step 2: 2.2 g of cobalt nitrate hexahydrate was weighed and dissolved in 40 mL of DMF to form solution B;

[0046] Step 3: Solution A and solution B were uniformly mixed under stirring for 20 min, and then 3 mL of ammonia water was added dropwise to the mixture to form solution C;

[0047] Step 4: After solution C was stirred at room temperature for 3 h, the purple solid was collected by centrifugation after washing with ethanol three times, and the purple solid powder S was obtained by drying at 70°C overnight;

[0048] Step 5: Potassium chloropalladite was mixed with the above-mentioned purple solid powder S at a mass ratio of 1:3 in 50 mL of deionized water; magnetic stirring was performed for 12 h to obtain suspension D;

[0049] Step 6: The precipitate was collected by centrifugation from suspension D, and the precipitate was washed with deionized water several times until the washing liquid was neutral. The collected dark purple solid SS was freeze-dried;

[0050] Step 7: The dark purple solid SS in step 6 was placed in a crucible and heated in a muffle furnace at 300°C for 2 h, and then cooled to room temperature to obtain (K2PdCl4)CoO x nanozyme.

[0051] Comparative Example 2:

[0052] Step 1: 2.3 g of benzimidazole was dissolved in 100 mL of N,N'-dimethylformamide (DMF) to form solution A;

[0053] Step 2: 2.2 g of cobalt nitrate hexahydrate was weighed and dissolved in 40 mL of DMF to form solution B;

[0054] Step 3: Solution A and solution B were uniformly mixed under stirring for 20 min, and then 3 mL of ammonia water was added dropwise to the mixture to form solution C;

[0055] Step 4: After solution C was stirred at room temperature for 3 h, the purple solid was collected by centrifugation after washing with ethanol three times, and the purple solid powder S was obtained by drying at 70°C overnight;

[0056] Step 5: The dark purple solid SS in step 4 was placed in a crucible and heated in a muffle furnace at 300°C for 2 h, and then cooled to room temperature to obtain CoO x nanozyme.

[0057] The nanozymes prepared in Example 1 and Comparative Examples 1 and 2 were subjected to oxidation enzyme activity detection, and the specific steps were as follows:

[0058] 1. The nanozyme prepared in Example 1, Comparative Example 1 and 2 was prepared into a suspension of 200 μg / mL, and ultrasonic treatment was performed for 30 min.

[0059] 2. 250 μL of the suspension of each of the nanozymes was taken and added to 2 mL of an acetic acid buffer (0.2 M, pH 3.5), followed by the addition of 125 μL of hydrogen peroxide (2 mM), mixing, incubation at 37 °C for 20 min, and the addition of 125 μL of a substrate. The absorbance (A) of the mixture at 652 nm was measured. 652

[0060] The substrate in Step 2 was one of 3,3',5,5'-tetramethylbenzidine (TMB), o-phenylenediamine (OPD), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS).

[0061] From Figure 2 it can be seen that the A652 value of the nanozyme prepared in Example 1 was significantly increased, while the A652 values of Comparative Examples 1 and 2 were small, which indicated that the PdCoO x nanozyme had high peroxidase-like activity.

[0062] Application Example 1

[0063] The PdCoO x nanozyme prepared in Example 1 was applied to the detection of H2O2, and the specific steps were as follows:

[0064] 1. An acetic acid-sodium acetate buffer (pH 3.5, 0.2 M), PdCoO x nanozyme (final concentration 20 μg / mL), TMB (final concentration 150 μM), and H2O2 (final concentration in the range of 0-400 μM) solutions were mixed.

[0065] 2. Incubation at 37 °C for 20 min.

[0066] 3. The absorbance value of the mixture at 652 nm was measured and recorded by using a UV-visible spectrophotometer.

[0067] As shown in Figure 3 A, the catalytic activity of the PdCoO x nanozyme depended on the concentration of H2O2, and thus the PdCoO 652 nanozyme could be directly applied to the detection of H2O2. The absorbance value ΔA increased with the increase of the concentration of H2O2. The ΔA and the concentration of H2O2 were linearly related in the range of 0.01-100 μM. The linear equation was ΔA=0.005[H2O2] (μM)+0.146 (r 2 = 0.983). Moreover, the detection limit of the method for H2O2 was 10 nM.

[0068] ​Application Example 2

[0069] The PdCoO prepared in Example 1 x The specific steps for applying nanozymes to glucose detection are as follows:

[0070] 1. First, add 0.1 mL of glucose oxidase solution (1 mg / mL) and 0.1 mL of glucose solution (0-1000 μM) to 0.5 mL of acetate-sodium acetate buffer (0.2 M, pH 7.0).

[0071] 2. After incubating at 37℃ for 30 min, add TMB solution (final concentration 150 μM) and PdCoO2. x The nanozyme suspension (final concentration 20 μg / mL) and 0.2 M acetate-sodium acetate buffer (pH 3.5) were incubated at 37 °C for 20 min.

[0072] 3. Measure and record the absorbance of the mixture at 652 nm using a UV-Vis spectrophotometer.

[0073] Glucose can be oxidized by dissolved oxygen in the presence of glucose oxidase (GOx) to produce H2O2 molecules. Therefore, PdCoO2, which binds to GOx, exhibits peroxidase-like catalytic activity. x The material can be used to determine glucose content. Figure 3 B shows that the absorbance value at 652 nm (A652) increases with increasing glucose concentration, and there is a linear relationship between ΔA and glucose concentration in the range of 0.1-400 μM. The obtained linear equation is ΔA = 0.0001[glucose](μM) + 0.14857(r 2 =0.967), the detection limit of this method for glucose detection is as low as 0.1 μM.

[0074] Application Example 3

[0075] The PdCoO prepared in Example 1 x Nanozymes are used to scavenge free radicals, and the specific steps are as follows:

[0076] 1. Mixed acetate-sodium acetate buffer (pH 3.5, 0.2M), PdCoOx nanozyme (final concentration 20 μg / mL), TMB (final concentration 150 μM), H2O2 (final concentration range 150 μM) solution, AA (O2 ·- and ·OH scavenger), NaN3 ( 1 O2 scavenger), thiourea (TH) (·OH scavenger), and p-benzoquinone (PBQ) (O2· - (Cleanser).

[0077] 2. Incubate at 37℃ for 20 minutes.

[0078] 3. Measure and record the absorbance of the mixture at 652 nm using a UV-Vis spectrophotometer. For example... Figure 4 As shown, with the increase of the concentration of each free radical, A 652 The value decreases, indicating that PdCoO x The catalytic properties of nanozymes lie in their ability to scavenge free radicals.

[0079] To gain a deeper understanding of its catalytic mechanism, AA(O2) was used. ·- and ·OH scavenger), NaN3 ( 1 O2 scavenger), thiourea (TH) (·OH scavenger), and p-benzoquinone (PBQ) (O2 scavenger). ·- Free radical scavengers, including O2, were investigated to identify potential intermediate reactive oxygen species (ROS, including O2) generated in the TMB / H2O2 / Cu-NC-700 system. ·- , 1 O2 and ·OH).

[0080] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the application of the present invention is not limited to the examples described above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing MOF-derived bimetallic oxide nanozymes, characterized in that... Includes the following steps: 1) Dissolve benzimidazole in N,N'-dimethylformamide to prepare solution A, wherein the concentration of benzimidazole in solution A is 2-3%; 2) Dissolve cobalt nitrate hexahydrate in N,N'-dimethylformamide to prepare solution B, wherein the concentration of cobalt nitrate in solution B is 5-6%; 3) Mix solution A and solution B thoroughly, then add ammonia dropwise to the mixture and stir to form solution C. The mixing time for solution A and solution B is 15-30 minutes, and the amount of ammonia added is 2-3% of the total volume of solution A and solution B. 4) Stir the above solution C at room temperature, wash with ethanol, centrifuge to collect the purple solid, and dry overnight to obtain purple solid powder S; 5) Palladium nitrate and the above-mentioned purple solid powder S were mixed in deionized water and magnetically stirred to obtain suspension D; 6) Centrifuge the above suspension D to collect the precipitate, wash the precipitate several times with deionized water until the washing liquid is neutral, and freeze-dry the collected dark purple solid SS. 7) Place the above dark purple solid SS in a crucible, heat it in a muffle furnace, and cool it to room temperature to obtain MOF-derived bimetallic oxide nanozymes, namely PdCoO. x Nanozymes.

2. The method for preparing a MOF-derived bimetallic oxide nanozyme as described in claim 1, characterized in that... In step 4), solution C is stirred at room temperature for 3 to 5 hours.

3. The method for preparing a MOF-derived bimetallic oxide nanozyme as described in claim 1, characterized in that... In step 5), the mass ratio of palladium nitrate to purple solid powder S is 1:3-5.

4. The method for preparing a MOF-derived bimetallic oxide nanozyme as described in claim 1, characterized in that... In step 7), the heating temperature of the muffle furnace is 300-400℃, and the heating time is 2-3 hours.

5. MOF-derived bimetallic oxide nanozymes obtained by the preparation method according to any one of claims 1-4.

6. The application of the MOF-derived bimetallic oxide nanozyme as described in claim 5 as a peroxidase.

7. The application of the MOF-derived bimetallic oxide nanozyme as described in claim 5 in the scavenging of free radicals.

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